This is perhaps the most easily recognized member of the P. capillare complex with the small (1.5–1.9 mm long, 0.6–0.8 mm wide) spikelets arrayed in racemose groups of 2–6 at the ends of the panicle branches giving a distinctive look. It is a species primarily of moist sandy or mucky shores of lakes and streams, including the Great Lakes, where the zigzag, partly decumbent culms are a distinctive, if uncommon, feature in late summer, especially during low water level years. It is rarely found in weedy habitats. This is a more northern species, nearing the southern limit of its range in southernmost Michigan. Considered by some authors to be the same as P. philadelphicum, and all records of P. philadelphicum from Michigan Flora belong here.